Question

我正在实施一些核心数据示例项目。我已经定义了一个mainManagedContext和一个privateManagedContext。

现在我的问题是，“如果我使用多个线程访问privateManagedContext，这是对的吗？”

提前谢谢。

Answer 1

In my experience with accessing at the same time the static context lead me to a crashes.

So the only solution that I've implemented is to make a copy of the managedObjectContext for each tread where i have to work and make all my function( add/edit/save) with context as parameter:

so in some thread make a copy of context:

NSManagedObjectContext *localContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
[localContext setPersistentStoreCoordinator:YourStaticManagedObjectContext.persistentStoreCoordinator];

and use that context in current thread (add/edit) then save context:

[YourManager saveContext:localContext withBlock:nil];

be careful if you need data at the same time when write in one thread and read on other thread better to implement some synchronized access to that staticManagedObjectContext.

Answer 2

您需要参考本指南：

https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/CoreData/Concurrency.html

简而言之，您通常无法从多个线程引用相同的托管对象上下文。除非您相应地设置并发策略。但是，即使这样，你也不会真正实现并发I / O操作（这是因为并行I / O通常比较慢，除其他原因之外）。

你想做什么？

多个线程可以访问单个privateManagedContext吗？

2 个答案: